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Thursday, April 16, 2015

Having a Hot Hand Increases Confidence, But Not Success

One of the great things about doing research is that you can
actually test the beliefs that people take for granted.And sometimes, those beliefs are shown to be
false.A classic example of this approach
comes in the belief in a hot hand in
basketball.When you watch a basketball
game, a player will make a couple of shots, and the announcers will decide that
player is “on fire” and that he ought to take the team’s next shot.

Back in 1985, though, Tom
Gilovich, Robert Vallone, and Amos Tversky actually analyzed data from the
Philadelphia 76ers.They found no
evidence for a hot hand.The hot hand
would say that if a player makes one shot, then they should be more likely to
make a second.Gilovich, Vallone, and
Tversky found that the probability that a player would make a second shot was
independent of whether they made the first one, suggesting that there is no hot
hand.

An interesting question, though, is whether the belief in
the hot hand influences the behavior of the players themselves. That question
was explored in analyses by Yigal Attali reported in the July, 2013 issue of Psychological Science.He analyzed all of the data from every game
in the 2010-2011 National Basketball Association season.Modern transcripts for games include lots of
information including who took each shot, whether it was made, and the distance
of the shot.

Attali found evidence that the belief in a hot hand did
affect the behavior of players.When a
player made one shot, it affected whether they would take the team’s next
shot.When the shot was from a short
distance (a dunk or layup), then players took about 20% of their team’s next
shots regardless of whether they made or missed the shot.However, when they made a shot that was
longer than 4 feet, they were much more likely to take the team’s next shot
than if they missed that shot.

That’s not all.When
players made a shot, the next shot they took was generally further from the
basket than when players missed their last shot.Because longer shots probably reflect that a
player has more confidence in his ability, this suggests that making a shot
increases a player’s confidence.

Paradoxically, though, this confidence has a cost.Longer shots are more likely to be missed
than shorter shots, so when a player takes two shots in a row, he is much more
likely to miss the second shot than to make it, because the second shot is
probably taken from further away following a hit than following a miss.(Indeed, Attali re-analyzed the data from the
Philadelphia 76ers that Gilovich, Vallone, and Tversky used, and found a similar
effect that when a player makes one shot, they are actually less likely to make
the second shot than when they missed the previous shot.)

Finally, Attali explored the effect of making a shot on the
behavior of coaches.He found that
players were much less likely to be taken out of a game following a made shot
than following a missed shot.So,
coaches are also acting as though they believe in a hot hand.

What does all of this mean?

In lots of domains (including basketball), we have theories
about the way the world works.Those
theories influence our actions.However,
it is important to know whether our theories about the way the world works are
actually true.Sometimes, as in the case
of the hot hand in basketball, not only is the theory false, but acting based
on the theory also makes people’s performance worse than it would be if they
did not believe in the theory.